Conventional radiation therapy utilizes electron beams and x-rays as a means of treating and controlling cancer. Due to the inability of current technology to preferentially deposit the radiation at the site of the cancer, healthy tissues between the tissue surface and the cancer also receive high doses of radiation and, thus, are damaged. Consequently, physicians use a less-than-optimal dose to reduce the undesirable damage to healthy tissues and the subsequent side effects. In many cases, this proves to be an unacceptable alternative.
Proton therapy has proven to be a viable alternative to x-ray and electron beam therapy in cancer treatment. By offering greater precision than conventional radiation therapy, physicians are able to deliver higher, more effective doses to target volumes. Protons tend to travel through the body tissue without significant absorption until they reach a specific point within the body. At this point, which corresponds to the Bragg peak of the proton beam, the proton energy is released. Accordingly, when the Bragg peak of the proton beam corresponds with the target location to be treated, the target location receives the highest concentration of radiation. There is very little lateral secondary scatter and, thus, virtually no damage to surrounding healthy tissues. While the Bragg peak for monoenergetic proton beams permits the energy deposited by the beam to be concentrated at a particular site within the patient, the proton beam is typically only a few millimeters wide, which is insufficient for delivering a sufficient radiation treatment dose to irregularly-shaped three-dimensional treatment volumes, such as tumors, particularly if the treatment volumes are large.
Thus, there is a need for a radiation treatment system which will accurately and reproducibly deliver maximum, uniform radiation treatment to designated target volumes.